In general, an image taking optical system of a lens apparatus has optical aberration (chromatic aberration and distortion) and an image taken through the image taking optical system contains degradation components according to the optical aberration.
Therefore, a conventional image taking system uses a method of reducing degradation components by computing an optical aberration amount on an image pickup surface of a camera apparatus on which an object image is formed by a lens apparatus and performing image processing (correcting process) with respect to a taken image based on the optical aberration amount.
PTL 1 discloses a method in which a camera apparatus preliminary holds data (aberration correcting data) regarding optical aberration of a lens apparatus and performs aberration correcting process. The camera apparatus determines a correcting amount in correcting process using the aberration correcting data and parameters of optical adjusting members such as a zoom, a focus and an iris of the lens apparatus.
Further, PTL 2 proposes a camera apparatus that identifies lens number and type and reads accurate correcting data based on the lens number and type, regarding a procedure for exchanging data of an electronic still camera or a video camera with an interchangeable lens.
In the system in which correcting data is changed according to a kind and use status of a lens as disclosed in PTL 1 and PTL 2, correcting data sent by a lens is changed along with a change in an optical system or correcting data to be used is selected from correcting data stored in a camera body. However, such a system does not assume the case where one interchangeable lens is attached to multiple different camera bodies as in a broadcasting lens or the case where one interchangeable lens is attached to a camera body under different image taking situations and in different image taking modes.
Broadcasting cameras may be required to have different resolutions, such as those for a high definition (HD), a standard definition (SD) or a cinema. On the other hand, even when the same lens is used, different color properties may be obtained from a combination of the lens and a camera, depending upon the kind of the camera. Thus, in an image pickup system for broadcasting, it is necessary to consider the case where the same lens is attached to different kinds of cameras or the case where images are taken under different image taking situations or in different image taking modes, even using the same type of camera.
When the number of kinds of lens apparatuses that can be attached to a camera apparatus increases in an image taking system with an interchangeable lens, it is difficult to retain aberration correcting data corresponding to all the lens apparatuses in the camera apparatus. In order to address such a problem, a lens apparatus is configured to hold aberration correcting data and to send the correcting data to a camera apparatus so that correcting process is performed. However, considering an individual difference and a production error in the lens apparatus, irrespective of whether the camera apparatus or the lens apparatus holds the aberration correcting data, the apparatus has only uniform aberration correcting data for one type of apparatus. Therefore, it is difficult to cover the errors of all the attachable lens apparatuses and perform aberration correction appropriately.
Further, in the future, when a resolution increases more and more as seen in Super Hi-Vision (SHV) and a demand for aberration correction with respect to a camera apparatus and a lens apparatus increases, it is necessary to realize aberration correction considering an individual difference and a production error of lens performance for each type.
Under such circumstances, the following is desired. A lens apparatus is configured to have basic aberration correcting data and, the aberration correcting data is finely adjusted in the lens apparatus when the lens apparatus is attached to a camera apparatus. The data after being adjusted is sent to the camera apparatus so as to be used for correcting process in the camera apparatus.